When supplying relatively large amounts of beverage, in the order of tens of liters, to an establishment it is known to use refillable steel containers, in the case of beer and such, or heavy duty refillable or recyclable plastic containers, in the case of water for water dispensers. The steel containers or kegs are costly to produce and to keep in stock for a supplier of beverage, and after they have been emptied and prior to their return trip they demand a large storage volume for an end user. The steel kegs are rather heavy; a 20 liter keg weighs about 10 kg (empty).
WO 00/78665 discloses a beer container or keg comprising an inner hollow shell of blow moulded polyethylene terephtalate (PET), a rigid outer hollow shell of moulded high-density polyethylene enclosing and supporting the inner shell and a spear structure including a dispenser tube extending from a bottom interior region of the inner shell and through a dispensing outlet at the top of the outer shell. The above publication addresses the mentioned problem associated with steel containers but still only provides a partial solution since the container still is a relatively expensive and elaborate construction.
While the above known containers operate in a conventional way, by application of an internal pressure in order to force beer out of the container, an alternative solution is described in WO 99/11563. This known solution includes applying an outer pressure to a flexible container, said pressure being a mechanical pressure or a gas pressure. This known system also requires several accessories which makes it expensive and complicated.
WO 04/099060 describes a method for dispensing a beverage and devices therefor. The system is similar to the one previously mentioned by an external gas pressure being applied between the container and an outer housing, though the container is placed upside down in a tailor-made stand.
A further example of a plastic container for beer is described in WO 03/008293. However, this container is to be disposed in an outer casing, such as a box of metal or paperboard.
When non-carbonated or low-carbonated beverages have been filled in plastic containers, it has been necessary to use a container with relatively thick walls in order to ensure manageability and stability so that the container does not collapse when being handled and/or emptied. A known example is water containers adapted to be mounted upside down in a support, see for example U.S. Pat. No. 5,217,128. These containers have a wall thickness of about 0.8-1.0 mm in order to meet the demands of manageability and stability as mentioned above. During portion-by-portion dispensing from these containers, a sub-atmospheric pressure is generated inside the container, leading to surrounding air being drawn into the container. This has an injurious effect on the hygiene in the container and the quality of the water can consequently not be vouched for. Thick-walled containers result in increased production and transportation costs, relative to thin-walled containers. Further, the thick-walled containers demand larger resources in terms of disposal systems. This is especially a problem in developing countries where drinking water often needs to be transported in various kinds of containers to areas that do not have access to safe running water.